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What is the relationship between adherence to dietary guidelines/recommendations or specific dietary patterns (assessed using methods other than index/score, cluster or factor, or reduced rank regression analyses) and risk of cardiovascular disease?

Conclusion

There is strong and consistent evidence that consumption of a DASH diet results in reduced blood pressure in adults with above optimal blood pressure, up to and including stage 1 hypertension. A dietary pattern consistent with the DASH diet is rich in fruits, vegetables, low-fat dairy, fish, whole grains, fiber, potassium, and other minerals at recommended levels and low in red and processed meat, sugar-sweetened foods and drinks, saturated fat, cholesterol, and sodium. There is limited evidence that adherence to vegetarian diets is associated with decreased death from ischemic heart disease, with the association being stronger in men than in women.
 

Grade

I-Strong - DASH and Blood Pressure; III-Limited – Vegetarian and Ischemic Heart Disease

 

Key Findings:

  • Two types of dietary patterns were identified using other methods of assessing dietary exposure related to cardiovascular disease (CVD) risk: (1) a DASH dietary pattern and (2) a vegetarian-style dietary pattern.
  • Evidence from RCTs showed a DASH diet resulted in reduced blood pressure (BP) including systolic BP (SBP) and/or diastolic BP (BP) in adults with above optimal blood pressure, up to and including stage 1 hypertension, with further reductions with the low sodium DASH modification and the DASH high protein or DASH high unsaturated fat modifications (OmniHeart). Addition of a behavioral intervention or weight management intervention together with the DASH diet was more effective in reducing BP than DASH diet alone (PREMIER, ENCORE). Approximately two-thirds of the U.S. population has pre-hypertension or hypertension.
  • Evidence from prospective cohort studies showed a vegetarian diet was associated with reduced ischemic heart disease (IHD) or cardiovascular disease (CVD) mortality in four out of six studies. In studies that showed a favorable association for the vegetarian diet, the risk reduction for men was greater than that for women. The association between vegetarian diets and BP was less clear.
  • Studies that examined cerebrovascular disease or stroke mortality did not find differences between vegetarians and non-vegetarians.
  • The results of either a DASH diet or vegetarian diet on blood lipids were mixed regarding effects on total-, LDL-, and HDL-cholesterol and triglycerides.
  • The DASH diet is high in fruits, vegetables, low-fat diary, whole grains, fish, fiber, potassium, and other minerals at recommended levels and low in red and processed meat, sugar-sweetened foods and drinks, saturated fat, cholesterol, and sodium. Vegetarian diets include vegan (no meat, fish, eggs, or dairy). lacto-ovo vegetarian (includes eggs and dairy, but no fish or meat), and pesco vegetarian (includes fish, but no meat) diets.

Evidence Summary Overview

Description of the Evidence
A total of 20 articles met the inclusion criteria for this systematic review on dietary patterns and incident CVD outcomes assessed using methods other than index/score, cluster or factor, or reduced rank regression analyses. The body of evidence consisted of 14 articles from 8 randomized controlled trials (RCTs) (Adamsson, 2011; Appel, 1997 and 2005; Blumenthal, 2010, Blumenthal Babyak Sherwood, 2010; Conlin, 2000; Howard, 2006; Lien, 2007; Margetts, 1985; Moore, 1999; Obarzanek, 2001; Sacks, 2001; Saneei, 2013; Svetkey, 2004) and six prospective cohort studies (PCS) (Burr and Butland, 1988; Chang-Claude, 2005; Crowe, 2013; Key, 1996 and 1999; Orlich, 2013). In terms of study quality, 15 of the 20 articles received a positive quality rating and five were rated neutral (Burr and Butland, 1988; Chang-Claude, 2005; Key, 1996 and 1999; Margetts, 1985). The studies were carried out between 1985 and 2013. Twelve articles were from 6 RCTs and one PCS conducted in the United States; three PCSs were conducted in the United Kingdom, Australia, and Germany; and two RCTs were conducted in Sweden and Iran, and there was one pooled analysis of cohort studies conducted in the United States, United Kingdom, and Germany. The sample sizes of the RCTs ranged from 49 to 44,351 participants (12 studies <500; 1 study >500; 1 study >40,000) and the PCSs had sample sizes of 1,724 to 76,172 participants (1 study >1,000; 2 studies >10,000; 2 study >70,000). All of the studies were conducted with adults, with the exception of the RCT conducted in Iran on adolescent girls (Saneei, 2013). Eighteen out of 20 articles included men and women. One RCT included only post-menopausal women (Howard, 2006) and one RCT included only adolescent girls (Saneei, 2013). RCT duration ranged from 30 days to 8.1 years (9 <2 months; 4 <6 months; 1 >8 years) and PCSs ranged from a mean of 5.8 years to 21 years (1 <10 years; 2 >10 years; 1 >15 years; 1 >20 years).
 
Dietary patterns examined:
Ten of the 20 articles reported results from the original Dietary Approaches to Stop Hypertension (DASH) trial (Appel, 1997; Conlin, 2000; Moore, 1999; Obarzanek, 2001) or subsequent trials that examined either variations on the original DASH diet (Appe,l 2005 [Omni Heart]; Sacks, 2001 [DASH-sodium]; Svetkey, 2004 [DASH-sodium]) or added behavioral interventions to the original DASH diet in free-living populations (Blumenthal, 2010 [PREMIER]; Blumenthal Babyak and Sherwood, 2010 [PREMIER]; Lien, 2007 [ENCORE]). A small trial in Iran also tested a DASH diet modified for adolescents (Saneei, 2013). Three additional RCTs looked at a Nordic diet (Adamsson, 2011), a low-fat dietary pattern (Howard, 2006 [WHI-DM]), and an ovo-lacto-vegetarian diet (Margetts, 1985). The diets examined in the six PCSs were vegetarian, in some cases including pesco-vegetarian, lacto-ovo-vegetarian, and vegan diets (Burr and Butland, 1988; Chang-Claude, 2005; Crowe, 2013; Key, 1996 and 1999; Orlich, 2013).
 
Population:
The original DASH trial and subsequent DASH modification trials commonly included adult subjects that were generally healthy but with pre-hypertension or with untreated stage I hypertension. Additionally, Black and minority subgroups were well-represented in these trials, Blacks accounted for 39 to 65 percent of the trial populations, in addition to other minorities from 1 to 6 percent (Appel, 1997 and 2005; Blumenthal, 2010; Blumenthal Babyak and Sherwood, 2010; Conlin, 2000; Lien, 2007; Moore, 1999; Obarzanek, 2001; Sacks, 2001; Svetkey, 2004).
 
Dietary assessment:
Dietary intake in this review was assessed by adherence to a specific dietary pattern using a variety of methods (i.e., food frequency questionnaire [FFQ], food record/diary/checklists, 24-hour recall, responses to a “Yes/No” question asking if subjects were vegetarian), and urinary mineral and urea nitrogen analyses. 
 
The DASH and DASH-sodium trials were controlled feeding trials where subjects received prepared meals consumed on-site, with some meals consumed off-site. For each day of controlled feeding, subjects recorded their intake of discretionary items. They indicated whether they ate any non-study foods and whether they did not eat all the study foods. Adherence to the diet was further assessed by measuring 24-hour urinary sodium, potassium, phosphorous, and urea nitrogen. In the free-living ENCORE trial (DASH + Weight Management), as well as the Women’s Health Initiative Dietary Modification (WHI-DM) trial (low-fat diet), food intake was assessed with both FFQs and 4-day food records. In the PREMIER trial, dietary intake was assessed from two unannounced 24-hour dietary recalls conducted by telephone. Self-reported dietary intake was corroborated using the 24-hour urinary measures indicated above for DASH. The small DASH trial in Iran, small NorDiet trial in Sweden, and the small lacto-ovo vegetarian trial in Australia all used daily diet records to assess adherence.
 
Prospective cohort studies on vegetarian diets assessed dietary intake using FFQs (Crowe, 2013 [EPIC-Oxford]; Key, 1996; Chang-Claude, 2005 [German Vegetarian Study]; Orlich, 2013 [Adventist Health Study 2]). Of these studies, only one assessed dietary intake after baseline: Change-Claude (2005) conducted a follow-up on dietary changes at 5 and 11 years. However, a few studies only asked participants if they were a vegetarian (i.e., defined as those who did not eat meat or fish) (Key, 1999; Burr and Butland, 1988).
 

Qualitative Synthesis of the Collected Evidence

Themes and Key Findings
 
Health Outcomes:
The 20 articles in this review considered CVD risk factors, or intermediate outcomes, including hypertension, blood pressure, and blood lipids and endpoint health outcomes including CVD incidence or mortality.
 
Intermediate Outcomes:
Hypertension, Blood Pressure, and Blood Lipids:
Nine articles reported results from the DASH and modified DASH trials on the effect of dietary intake on changes in systolic and diastolic blood pressure (SBP and DBP) or ambulatory blood pressure (ABP) in prehypertensive and/or hypertensive adults (Appel, 1997 and 2005; Conlin, 2000; Howard, 2006; Lien, 2007; Margetts, 1985; Moore, 1999; Sacks, 2001; Svetkey 2004). Two of these articles also reported on hypertension/blood pressure control (Conlin, 2000; Svetkey, 2004). One article reported results from the WHI-DM trial with subjects who had blood pressure that was either treated, stage 1 hypertension, or strayed into the high end of the range (>140/90 mm) (Howard, 2006). One small trial reported on the effect of a Nordic diet on SBP and DBP (Adamsson, 2011). Lastly, in all of these studies subjects were not on anti-hypertensive medications, with one exception where medication was not indicated (Adamsson, 2011).
 
Six of the above articles also reported on blood lipids, including total cholesterol, low-density lipoprotein [LDL] cholesterol, high-density lipoprotein [HDL] cholesterol, and triglycerides [TG]) (Appel, 2005; Blumenthal Babyak and Sherwood, 2010; Howard, 2006; Lien, 2007; Obarzanek, 2001; Saneei, 2013). Adamsson (2011) only looked at LDL cholesterol.
 
DASH Trials:
Eleven of the 20 articles reported on the original DASH or a variation on the DASH trial (Appel, 1997 and 2005; Blumenthal, 2010; Blumenthal Babyak and Sherwood, 2010; Conlin, 2000; Lien, 2007; Moore, 1999; Obarzanek, 2001; Sacks, 2001; Saneei, 2012; Svetkey 2004).
 
DASH Trial: The original DASH trial compared a control diet that was typical of a substantial number of Americans with either (1) a fruits and vegetables diet or (2) a combination diet that was rich in fruits and vegetables and low-fat dairy foods. The trial showed that consumption of the combination diet (DASH) reduced SBP and DBP in prehypertensive and hypertensive adults (Appel, 1997). When hypertensive subjects in the DASH trial were assessed separately, the combination DASH diet resulted in a greater reduction in SBP and DBP in hypertensives than in non-hypertensives (Appel, 1997) and a 60 percent decreased risk of hypertension in this subgroup (Conlin, 2000). Ambulatory BP (ABP) was also assessed and the combination DASH diet resulted in lowered 24-hour ABP, and the hypertensives had a greater response than non-hypertensives to the combination DASH diet (Moore, 1999). Furthermore, the combination DASH diet resulted in lower total and LDL-cholesterol, but also lower HDL-cholesterol, and had no effect on triglycerides (Obarzanek, 2001). The net reduction in total- and LDL-cholesterol was greater in men than in women, but there were no differences based on race.
 
DASH-Sodium Trial: The DASH-sodium trial introduced three levels of sodium intake in the DASH diet and a typical U.S. control diet. The reduction in sodium resulted in significantly lowered SBP and DBP in both DASH and control groups; however, the DASH diet resulted in lower SBP than the control diet at every sodium level (Sacks, 2001). Additionally, reducing sodium intake from the high to the low level with either the DASH or control diets reduced SBP in subjects with and without hypertension, and in Blacks and other racial groups, as well as in men and women. But the combination of the two dietary interventions, DASH and low sodium, lowered SBP more in participants with HTN than in those without HTN, and more in women than in men (Sacks, 2011). Another report from the DASH-sodium trial examined BP control and found that the maximum BP control rate was achieved with the DASH/lower sodium treatment (Svetsky, 2004).
 
OmniHeart Trial: Trials that further assessed a DASH dietary approach with modifications included the OmniHeart Trial that assessed diets rich in carbohydrates, protein, or unsaturated fats (predominantly monounsaturated fats) in subjects with prehypertension and stage I hypertension. Although all treatment arms were rich in fruits and vegetables, low-fat dairy, fiber, and potassium and reduced in saturated fat, cholesterol, and sodium, the carbohydrate diet used in OmniHeart was similar to the original DASH diet and the other two treatment arms substituted either unsaturated fats or protein for carbohydrates as 10 percent of energy. All three diets decreased BP, LDL-cholesterol, and 10-year CHD risk (from the Framingham risk equation). However, BP, total- and LDL-cholesterol, triglycerides, and estimated 10-year CHD risk were all significantly improved in the high protein, compared to the high carbohydrate diet. And BP, HDL-cholesterol and triglycerides were significantly improved on the high unsaturated fat diet, compared to the high carbohydrate diet (Appel, 2005).
 
PREMIER Trial: The PREMIER Trial was a multicomponent lifestyle intervention in a free-living population that included (1) an advice only control group; (2) a group that received established behavioral intervention for lowering BP (EST); and (3) a group that received EST plus a DASH diet. In participants without metabolic syndrome (MetSyn), EST and EST + DASH equally reduced SBP. However, in subjects with MetSyn, only the combined EST + DASH intervention resulted in SBP reduction. The effects of the EST and EST + DASH interventions on blood lipids were mixed, with decreased total cholesterol and a trend to improve LDL-cholesterol in both MetSyn groups, but no effect of EST + DASH on triglycerides (Lien, 2007). 
 
ENCORE Trial: The Exercise and Nutrition interventions for CardiOvasculaR hEalth (ENCORE) trial was conducted in overweight or obese subjects with high BP and the results indicated that the DASH diet plus weight management was more effective in decreasing BP than the DASH diet alone (Blumenthal, 2010). A second report from the ENCORE trial showed that the DASH diet alone, although it caused a decrease in BP, did not decrease total-, LDL-cholesterol, or triglycerides (Blumenthal Babyak and Sherwood, 2010). 
 
Vegetarian Diets:
Three of the articles on vegetarian patterns measured BP or blood lipids (Burr and Butland, 1988; Crowe, 2013; Margetts, 1985). Burr and Butland reported that a vegetarian diet was associated with decreased levels of total cholesterol, compared to non-vegetarians; however, BP measurements were not different between the two groups (Burr and Butland, 1988). Margetts examined the effect of a lacto-ovo vegetarian diet on BP in mild hypertensives and found a decrease in SBP, but not DBP (Margetts, 1985). In a study of the EPIC-Oxford cohort, comparing a vegetarian to a non-vegetarian diet showed a reduction in SBP, but not DBP, in a small sub-sample of the cohort (Crowe, 2013). In addition, non-HDL-cholesterol was reduced in the vegetarian participants.
 
Other Diets:
Women’s Health Initiative - Dietary Modification Trial: Women in the low-fat diet treatment group of the WHI-DM trial had decreased DBP and LDL-cholesterol; however, other CVD risk factors were not different between groups (Howard, 2006).
 
Nordic Diet: In the NORDIET Trial, the effect of a Nordic diet, compared to a control typical Western diet, on CVD risk factors was assessed. The Nordic diet treatment caused a decrease in SBP, but not DBP. Additionally, total-, LDL-, and HDL-cholesterol, and the LDL/HDL ratio were decreased with the Nordic diet (Adamsson, 2011).
 
Endpoint Clinical Outcomes:
CVD Incidence and Mortality:
One trial, the WHI-DM Trial, examined the effect of a low-fat diet on incident (fatal and nonfatal) CVD, CHD, and stroke (Howard, 2006). Six prospective cohort studies examined only mortality and these examined the association between a vegetarian diet and ischemic heart disease (IHD) mortality (Burr and Butland, 1988; Chang-Claude, 2005; Crowe, 2013; Key, 1999; Orlich, 2013), cerebrovascular disease mortality (Burr and Butland, 1988; Key, 1996 and 1999), CVD mortality (Orlich, 2013), or mortality due to circulatory diseases (Chang-Claude, 2005). One trial examined risk of CHD using the Framingham risk equation (Appel, 2005).
 
 Vegetarian Diets: Four studies that examined IHD found that IHD mortality was decreased in vegetarians compared to non-vegetarians (Burr and Butland, 1988; Crowe, 2013; Key, 1999; Orlich, 2013). However, one of these studies, conducted with the Adventist Health Study 2 cohort, found the association only in men for both IHD and CVD mortality, not in men and women combined nor in women alone (Orlich, 2013). Key and colleagues conducted a pooled analysis of five prospective cohort studies and found that mortality from IHD was 24 percent lower in vegetarians compared to non-vegetarians. Additional analysis showed that in comparison with regular meat eaters, mortality from IHD was 34 percent lower in lacto-ovo vegetarians and 26 percent lower in vegans (Key, 1999). However, two studies that compared vegetarians with health-conscious non-vegetarians, found IHD mortality was not different between the two groups in the United Kingdom (Key, 1996) and German participants (Chang-Claude, 2005), nor was all circulatory disease mortality (Chang-Claude, 2005). In these two studies, one study was relatively small for a prospective cohort study (N = 1,724 subjects) (Chang-Claude, 2005) and one study did not define vegetarians beyond a direct question asked of the participants (i.e., if participants were vegetarian) (Key, 1996).
 
Studies that examined cerebrovascular disease or stroke mortality did not find differences between vegetarians and non-vegetarians (Burr and Butland, 1988; Key, 1996 and1999; Orlich, 2013).
 
Low-fat diet:
The WHI-DM trial examined the effects of a low-fat diet on incident CVD, CHD, and stroke and found no effect on risk in postmenopausal women (Howard, 2006). The WHI-DM intervention resulted in decreased total and saturated fat intake in the treatment group, but also increased intakes of fiber, vegetables and fruits, total and whole grains, and soy.
 
DASH diet (OmniHeart):
In a report from the OmiHeart trial, CHD risk was estimated using the Framingham risk equation (Appel, 2005). The calculated 10-year risk of CHD was decreased for all versions of the DASH diet (modified to be high in carbohydrate, protein, or unsaturated fat as an increase in 10 percent of energy). Furthermore, compared with the carbohydrate diet, both the protein and unsaturated fat diets resulted in greater reductions in CHD risk. (This result is also considered under intermediate outcomes.)
 
Sub-analysis–Gender:
One of the prospective cohort studies that examined total and cause-specific mortality found an association only in men for both IHD and CVD mortality, not in men and women combined, nor in women alone (Orlich, 2013). Further analysis of different types of vegetarian patterns showed that for pesco-vegetarians, compared to non-vegetarians, women and men and women combined (but not men alone) had reduced IHD mortality, but only men had reduced CVD mortality. Comparing lacto-ovo vegetarians to non-vegetarians, CVD mortality was decreased only in men. And in vegans, both IHD and CVD mortality were reduced only in men (Orlich, 2013). Earlier studies also found that although there was reduced IHD mortality in men and women in vegetarians compared to non-vegetarians, there was a greater reduction in men (Burr and Butland, 1988; Key, 1999).

Table 4-B-IV-1 Summary of Findings Blood pressure, blood lipids and risk of CVD/CHD

Qualitative Assessment of the Collected Evidence

Quality and Quantity
Quality of the studies was assessed by examining the scientific soundness of study design and execution to determine if there was bias in the findings related to outcomes. The majority of the evidence for this question consisted of positive quality studies (15 out of 20 studies), indicating potential low risk of bias overall. In addition, these studies directly addressed the question, especially related to blood pressure and, additionally, CHD mortality.
 
Consistency
Blood Pressure:
The evidence of a protective association between a DASH dietary pattern and blood pressure was consistent in all of the RCTs in adults in the general population and adults with hypertension.
CHD Mortality
Evidence from prospective cohort studies showed a vegetarian diet was associated with reduced ischemic heart disease (IHD) or cardiovascular disease (CVD) mortality in four out of six studies. In the two studies that did not find an association, one study was relatively small for a prospective cohort study (N = 1,724 subjects) (Chang-Claude, 2005), and one study did not define vegetarians beyond a direct question asked of the participants (i.e., if participants were vegetarian) (Key, 1996).
 
Impact
The body of evidence directly addressed the exposures and health outcomes of interest for this systematic review, with clinical trials that consistently showed that a DASH diet resulted in reduced blood pressure in prehypertensive and hypertensive adults, thus decreasing CVD risk. In the DASH-sodium trial, the effect of DASH diet and low sodium achieved the greatest effect on blood pressure and the effect was equal to or greater than that of a single therapeutic drug for hypertensive individuals (Sacks, 2001). In addition, this body of evidence included large prospective cohort studies that found a favorable association between vegetarian diets and risk of mortality from ischemic heart disease (IHD), especially in men.
 
Generalizability/External Validity
Twelve articles from six RCTs and one PCS were conducted in the United States, with the remaining articles from studies conducted in the United Kingdom, Germany, Sweden, Australia, and Iran. Results from the DASH trials should be broadly applicable to the U.S. population as the trial populations were large and demographically heterogeneous. Additionally, DASH trials focused on individuals with prehypertension and hypertension, a group that makes up approximately two-thirds of the U.S. population. DASH trials were also conducted in free-living populations and found effective (PREMIER and ENCORE). Regarding the association between vegetarian diets and IHD mortality, two recent prospective cohort studies with large cohorts (EPIC-Oxford and Adventist Health 2) showed an association with reduced IHD death, as did one pooled analysis of five prospective cohort studies covering the United States, United Kingdom, and Germany. Given the robust evidence involving U.S. clinical trials and large cohort studies with endpoint mortality outcomes, the generalizability to the U.S. population, and the relevance of this body of evidence to U.S. policy, is compelling.

Table 4-B-IV-2 Overview Table: Cardiovascular Disease Organized by dietary trial/dietary pattern
 

Limitations of the Evidence

In the DASH trials, including the original DASH and DASH-sodium, the feeding phases were relatively brief (4-8 weeks) and the trial outcomes were CVD risk factors, not clinical events. In DASH trials with free-living populations, including PREMIER and ENCORE, there was the potential for selection bias, as participants may have been more motivated toward behavior modifications.
 
The studies on vegetarian diets were all prospective cohort studies, and there was the potential for vegetarian cohorts to be relatively health conscious in other lifestyle components, in addition to diet. Additionally, in these studies, analyses relied on single baseline measurements of diet, without further dietary intake assessment over the time course of prospective studies. Related to the specific systematic review question on dietary patterns, vegetarian diets including vegan, lacto-ovo vegetarian, and pesco vegetarian, were most-often described by what was excluded from the diet rather than a full dietary pattern including all foods and beverages consumed. Overall, the definition of vegetarian diets has not been standardized. 
 

Research Recommendations

Vegetarian diets are often defined by what is excluded from the diet rather than what is included; therefore, researchers should make efforts to characterize the diets of self-identified vegetarians more fully in terms of their patterns of food choice. In addition, standardization of the various definitions of vegetarian diets across different populations and locations would further advance knowledge in this area. The benefits of vegetarian diets are associated, in part, with decreased consumption of animal products; given this, it would help to inform policy if investigators could determine how much of a decrease in animal product consumption is most beneficial related to CVD risk. Methodologically, research in this area could be further improved by measuring dietary intake at regular intervals over the course of prospective studies, rather than just at baseline.
 
Further research needs to be done to clarify the effect of a DASH diet on blood pressure outcomes by racial/ethnic subgroups, as well as gender differences in blood lipid measures. The potential gender difference in the association between vegetarian diets and CHD mortality (i.e., more pronounced in men) needs to be further clarified, and this could be informed by detailed analyses of different forms of vegetarian diets including vegan, lacto-ovo vegetarian, and pesco-vegetarian diets, together with a fuller accounting of what these diets include as well as exclude.  Women’s diets tend to have higher diet quality with regard to a number of dietary dimensions other than protein sources which could explain why this particular exclusion does not have as pronounces an effect among them.
 

Abbreviations

Diet Trials and Cohorts: Dietary Approaches to Stop Hypertension (DASH); European Prospective Investigation into Cancer and Nutrition (EPIC); Exercise and Nutrition interventions for CardiOvasculaR hEalth (ENCORE); Nordic Diet (NorDiet); Optimal Macronutrient Intake Trial to Prevent Heart Disease (OmniHeart); Women’s Health Initiative (WHI) Dietary Modification (DM) Trial; The Multi-Ethnic Study of Atherosclerosis (MESA); The Netherlands (NL), British Civil Service cohort (Whitehall study) 
 

REFERENCES of Included Articles

See Search Plan for CVD


Research Design and Implementation
For a summary of the Research Design and Implementation results, click here.
Worksheets
Adamsson V, Reumark A, Fredriksson IB, Hammarström E, Vessby B, Johansson G, Risérus U. Effects of a healthy Nordic diet on cardiovascular risk factors in hypercholesterolaemic subjects: A randomized controlled trial (NORDIET). J Intern Med. 2011 Feb; 269(2): 150-159.

Appel LJ, Moore TJ, Obarzanek E, Vollmer WM, Svetkey LP, Sacks FM, Bray GA, Vogt TM, Cutler JA, Windhauser MM, Lin PH, Karanja N. A clinical trial of the effects of dietary patterns on blood pressure. DASH Collaborative Research Group. N Engl J Med. 1997 Apr 17; 336(16): 1,117-1,124.

Appel LJ, Sacks FM, Carey VJ, Obarzanek E, Swain JF, Miller ER, Conlin PR, Erlinger TP, Rosner BA, Laranjo NM, Charleston J, McCarron P, Bishop LM for the OmniHeart Collaborative Research Group. Effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids: results of the OmniHeart randomized trial. JAMA. 2005; 294: 2,455-2,464.

Blumenthal JA, Babyak JA, Sherwood A, Craighead L, Pao-HWa L, Johnson J, Watkins LL, Wang JT, Kuhn C, Feinglos M, Hinderliter A. The effects of the dash diet alone and in combination with exercise and caloric restriction on insulin sensitivity and lipids. Hypertension. 2010; 55(5): 1,199-1,205.  

Burr ML, Butland BK. Heart disease in British vegetarians. Am J Clin Nutr. 1988 Sep; 48(3 Suppl): 830-832.

Chang-Claude J, Hermann S, Eilber U, Steindorf K. Lifestyle determinants and mortality in German vegetarians and health-conscious persons: results of a 21-year follow-up. Cancer Epidemiol Biomarkers Prev. 2005; 14(4):963-8.  

Conlin PR, Chow D, Miller III ER, Svetkey LP, Lin PH, Harsha DW, Moore TJ, Sacks FM, Appel LJ, for the DASH Research Group.  The effect of dietary patterns on blood pressure control in hypertensive patients:  results from the Dietary Approaches to Stop Hypertension (DASH) trial.  Am J Hypertens 2000;13:949-955.

Crowe FL, Appleby PN, Travis RC, Key TJ. Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: Results from the EPIC-Oxford cohort study. Am J Clin Nutr. 2013 Mar; 97(3): 597-603.

Howard, B.V., Van Horn, L., Hsia, J., Manson, J.E., Stefanick, M.L., Wassertheil-Smoller, S., Kuller, L.H., Lacroix, A.X., Langer, R.D., Lasser, N.L., Lewis, C.E., Limacher, M.C., Margolis, K.L., Mysiw, W.J., Ockene, J.K., Parker, L.M., Perri, M.G., Phillips, L., Prentice, R.L., Robbins, J., Rossouw, J.E., Starto, G.E., Schatz, I.J., Snetselaar, L.G., Stevens, V.J., Tinker, L.F., Trevisan, M., Vitolins, M.Z., Anderson, G.L., Assaf, A.R., Bassford, T., Beresford, S.A., Black, H.R., Brunner, R.L., Brzyski, R.G., Caan, B., Chlebowski, R.T., Gass, M., Gramek, I., Greenland, P., Hays, J., Heber, D., Heiss, G., Hendrix, S.L., Hubbell, F.A., Johnson, K.C., Kotchen, J.M. Low-fat dietary pattern and risk of cardiovascular disease: The women's health initative randomized controlled dietary modification trial. Journal of the American Medical Association 2006; 295(6): 655-666.

Key TJ, Thorogood M, Appleby PN, Burr ML. Dietary habits and mortality in 11,000 vegetarians and health conscious people: results of a 17 year follow up. BMJ. 1996:28;313:775-779.

Key TJ, Fraser GE, Thorogood M, Appleby PN, Beral V, Reeves G, Burr ML, Chang-Claude J, Frentzel-Beyme R, Kuzma JW, Mann J, McPherson K. Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies. Am J Clin Nutr. 1999 Sep; 70 (3 Suppl): 5,16S-5,24S. PMID: 10479225.

Lien LF, Brown AJ, Ard JD, Loria C, Erlinger TP, Feldstein AC, Lin PH, Champagne CM, King AC, McGuire HL, Stevens VJ, Brantley PJ, Harsha DW, McBurnie MA, Appel LJ, Svetkey LP. Effects of PREMIER lifestyle modifications on participants with and without the metabolic syndrome. Hypertension, 2007 Oct; 50 (4): 609-616. Epub 2007 Aug 13. PMID: 17698724.

Margetts BM, Beilin LJ, Armstrong BK, Vandongen R. A randomized control trial of a vegetarian diet in the treatment of mild hypertension. Clin Exp Pharmacol Physiol. 1985;12(3):263-266.

Obarzanek E, Sacks FM, Vollmer WM, Bray GA, Miller ER 3rd, Lin PH, Karanja NM, Most-Windhauser MM, Moore TJ, Swain JF, Bales CW, Proschan MA; DASH Research Group. Effects on blood lipids of a blood pressure-lowering diet: the Dietary Approaches to Stop Hypertension (DASH) Trial. American Journal of Clinical Nutrition. 2001. 74(1):80-9.

Orlich MJ, Singh PN, Sabaté J, Jaceldo-Siegl K, Fan J, Knutsen S, Beeson WL, Fraser GE. Vegetarian dietary patterns and mortality in adventist health study 2. JAMA Intern Med. 2013 Jul 8; 173(13): 1,230-1,238.

Sacks FM, Svetkey LP, Vollmer WM, Appel LJ, Bray GA, Harsha D, Obarzanek E, Conlin PR, Miller ER 3rd, Simons-Morton DG, Karanja N, Lin PH. Effects on blood pressure of reduced dietary sodium and the dietary approaches to stop hypertension (DASH) diet. New England Journal of Medicine. 2001 Jan 4; 344 (1): 3-10.

Saneei P, Hashemipour M, Kelishadi R, Rajaei S, Esmaillzadeh A. Effects of recommendations to follow the Dietary Approaches to Stop Hypertension (DASH) diet vs. usual dietary advice on childhood metabolic syndrome: A randomised cross-over clinical trial. Br J Nutr. 2013 Jun; 18: 1-10.

Svetkey, L.P., Simons-Morton, D.G., Proschan, M.A., Sacks, F.M., Conlin, P.R., Harsha, D., Moore, T.J. Journal of Clinical Hypertension 2004; 6(7): 373-381.